Splendour & Squalor: 'treads a fine line between elegy and disapproval.'

On his wedding night, John Hervey, 7th Marquess of Bristol, shut himself into the morning room of his grand house with two of his closest friends. Soon, there was a timid knock and his new wife appeared. Marcus Scriven relates what happened next:

"John was the first to speak. He kept it brief. 'Fuck off'.

'I want to go to bed now, John.'

'Go to bed then.'

'John, it's my wedding night.'

'I love these two men more than I'll ever love you.' John cackled... there were just two other sounds – Francesca crying and her retreating footsteps."

This charming exchange pretty much sums up Hervey. And yet in his depiction of the marquess and three other 20th-century aristocratic calamities, Scriven avoids being judgmental. He treads a fine line between elegy and disapproval. By pitching his tone right, and providing plenty of juicy details, he has produced a work of wide appeal which manages to do justice to the fact that, privilege and scandal aside, the lives he depicts are rather sad.

The diligently researched book is split into four parts – one for each of the disastrous toffs selected, as Scriven explains, for the memorable havoc they wreaked. Besides John Hervey, the cast includes Edward FitzGerald, 7th Duke of Leinster, who committed suicide after losing his £400m fortune; 21-stone Angus Montagu, 12th Duke of Manchester; and John Hervey's father, the playboy jewel thief, Victor Hervey (also the father, by a later wife, of modern-day celebrities Lady Victoria and Lady Isabella).

Once, a duke would have wanted to be enormous, his fatness indicating wealth and a diet of rich foods. These days, the "formidable bulk" of the 12th Duke of Manchester is cited by Scriven as an indicator of the sad depth to which he had fallen by the time he died, alone, in a small apartment in a modern, low-rise block called Broadreach. Not that his immobility had stopped him taking advantage of the House of Lords, where he made a pretty strong one-man case for scrapping the hereditary system, thanks to his liberal use of the subsidised bars and restaurants.

Yet his life story, which included a stay at the Federal Correctional Institute at Petersburg, Virginia, reveals an insecure and sympathetic man, not the brute he first appears. As a child, he was an incorrigible fantasist: rather than being smug about who he was, he dreamed of escaping on elephants and shaking hands with Chairman Mao. Later, when the dukedom was in sight, he developed an obsession with it, leading him to believe that he could never tip less than £10 or let anyone else pick up a restaurant bill.

Still later he was, as Scriven puts it, "serenely ignorant that he was a peripheral figure in the world of organised crime". This may sound like a desperate defence, but he probably was too stupid to realise. An English judge, acquitting him of yet another misdemeanour, reflected that in ranking intelligence from one to 10, it was "kind" to put Montagu on the scale at all.

Not everyone in the book is so dim, least of all the supporting cast of conmen and seductresses. It's a pity that there is no index provided to make identification easier. In its absence, Scriven's "Notes" are useful; indeed, they are sometimes more compelling than the rest of the book, which suggests that shorter biographies of a greater number of these people might have made for an even more entertaining work. As it is, Splendour and Squalor risks falling somewhere between biography and enjoyable loo book.